Approximately one in every two American humans has an allergy to some antigen, and suffers, to some extent, from the reactions of his or her body's immune system. Allergies are a reaction of the immune system to a foreign substance. People who have allergies generally have a hyper-alert immune system that reacts to a substance in the environment, called an allergen. If one's immune system does not respond to the foreign substance, the allergen, then one is not allergic to that substance.
Allergic reactions are found in all animals that have immune systems. The tendency to have allergies, or have a responsive immune system, is inherited. Offspring do not inherit allergies to the same allergens that the parents had, just that the offspring will more likely be reactive to foreign substances. When one parent is allergic, the offspring has a 50% chance of having allergies. That risk jumps to 75% if both parents have allergies.
Allergies can be seasonal or year-round and include reactions caused by pollen, mold, insects, insect bites or stings, animal hair and dander, dust mites and other common substances in the environment. If the allergen is in the environment, such as air, surfaces, food or drink, and then contacts the human or animal, the immune system of the human or animal responds to the allergen. The body responds in a variety of ways to the allergen.
In general, when a person or animal is exposed to an allergen, a series of events takes place. The body makes a particular type of antibody, known as IgE, that has a binding particularity for the allergen. The antibodies associate with a mast cells which contain many reactions compounds, including histamine. Mast cells are found in large numbers in the airways and in the GI tract, areas where allergens can enter the body. Once the allergen is bound by the IgE on the mast cell, the mast cell is triggered to release its reactive compounds, particularly histamine, which may cause the itchiness or runny nose associated with allergic reactions.
The point of entry of the allergen into the body may decide the type of reaction that the immune system produces. If the allergen is in the air, the symptoms of the allergic reactions will include reactions in the eyes, nose and lungs. If the allergen enters through the gastrointestinal tract, the reactions will occur in the mouth, stomach and intestines. Sometimes there are systemic responses that occur regardless of the entry point of the allergen. Such responses include hives, decreased blood pressure, anaphylactic shock, or loss of consciousness. Responses to allergens may be mild, annoying or life-threatening.
Pharmaceutical agents, prescription or over-the-counter, are often used to treat the symptoms and stop the secondary effects of mast cell release, and include widely used agents such as antihistamines, inhaled steroids, nasal decongestants and cromolyn. Another approach to treatment of allergic reactions is immunotherapy, which is most frequently administered as injections, and is known as allergy shots. Allergy shots, as currently administered into the subcutaneous region of the forearm are an effective method of long-term relief from allergy symptoms. Patients are given the allergen in increasing doses until the body no longer responds in an allergic reaction to the allergen in the environment.
Many humans or animals with allergies do not get immunotherapy. Most treat the symptoms with pharmaceutical agents, just suffer through the seasons of pollen, grass or mold, or get rid of the allergen source, such as a pet. Surveys have shown that two in three people with allergies would never consider getting allergy shots. An even higher number of people would not consider such a treatment for their pets or livestock. Thus, many people and animals are suffering needlessly or constantly being medicated.
There are many reasons this type of immunotherapy, allergy shots, is avoided. Pain and annoyance are probably major considerations for avoidance. The offending allergen or allergens must be identified and this is done most often by immediate hypersensitivity testing, such as scratching the skin with a panel of allergens and noting the levels of itchiness, redness and swelling of each site.
Once the allergen is identified as one which causes an allergic reaction, and allergy shots are proposed, the patient must cooperate to a large degree in participating in this treatment regimen. Before every shot is administered, for two hours prior to and two hours after the shot, the patient should not exercise or engage in vigorous activity. Exercise may stimulate increased blood flow and promote a faster release of the allergen from the allergen depot in the arm to the bloodstream and trigger a more violent response. This level of inactivity may be problematic when treating animals and children. Taking medications, such as beta-blockers or monamine oxidase inhibitor (MAOI), may interfere if treatment is needed for the response to the allergy shot.
After receiving the shot, the patient must be monitored for thirty minutes to check for intense reactions, and avoid exercise for two hours. Redness, swelling, or irritation within one inch of the site of the injection is normal. These symptoms should go away within 4 to 8 hours after receiving the shot.
This is the outlook for the patient who must visit the physician or veterinarian weekly or bi-weekly for two to four years for these injections. Again, more pain and annoyance is involved in making and attending the appointments and receiving injections. After this series of shots, most patients are placed on several years of maintenance shots. This is an expensive and time-consuming regimen for treatment of an illness that is usually not life-threatening.
There is some danger in receiving allergy shots. The shot includes the very allergen for which the patient has a known immune response. If the immune response is triggered to react in an intense manner, the patient may die from anaphylactic shock. This is one reason a series of allergy shots may take from three to five years to reach a maintenance level. If the allergen is delivered at a faster rate, resulting in larger doses of the allergen, it may be dangerous for the patient. It is not recommended for patients with heart disease or severe asthma to even receive allergy shots.
The current therapeutic regimen for providing allergen compositions for allergy shots requires careful monitoring and preparation of the compositions by or under the control of a physician or veterinarian. Currently, only subcutaneous shots are approved by the FDA. The series of shots begins with a very dilute solution of the allergen and over time, increasing amounts of the allergen are injected using solutions having higher concentrations of the allergens. It usually takes several months and may take up to 2 years to reach a maintenance dose. Patients may experience some relief within 6 months; however, if there is no benefit within 18 months, the shots are generally discontinued.
What is needed are methods and compositions for treatment of allergic reactions that are easier to administer, with less pain, and are effective for immunotherapy for the relief of allergies. Methods that do not require constant office visits or complete physician or veterinarian oversight would also be advantageous. Methods and compositions that are easily administered to humans or animals without the need for dilution calculations to provide increasing amounts of allergen to the patient are needed for more universal use and acceptance by patients with allergy.